Vulcanizer



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UNITED STATES lMT1-:NT 1OFFICE.l

JAMES A. CROSS, E DENVER, COLORADO.`

vULoANIzER.

Application tiled May 10, 1926. Serial No, 108,006.

This invention relates to improvements in I the construction of vulcanizers of the type employed in the repairy of automobile tires and tubes and has reference more,part1cu. larly to the construction of an electrically heated. apparat-us of this type.l

In repairing tires and tubes it is necessary to heat the material to a predetermmed temperature for a given length of time so as to 'properly cure the rubber. If the temperature fails to reach the desirable value or eX- ceeds it, the results are not the best. It is,

' that when an electric heating element is used some thermoresponsive means must.r be employed to indicate the temperature and for this purpose it is customary to employ a thermometer. Where an electricheating ele- 'ment is employed and where a thermometer is used for determining the temperature, the operator must carefully observe the temperature and open and close theelectric circuit in accordance with the temperature indications.

It is evident that an electrically heated devicewould be' much more conveniently operatedpif it were provided with an automatic mechanism for controlling the temperature and one of the objects of this invention is to .produce an electric vulcanizer provided with such thermal control. The above and other objects that may become apparent as the description proceeds are obtained by means of a construction that I will now proceed to describe in detail, reference for this purpose .being had to the 1accompanying drawing-in which the invention has been illustrated and in which:

Fig. 1 is a t`op plan view of one of my improved electric vulcanizers; y

Fig. 2 is a transverse section taken on line 2 2', Fig. l; y

Fig. 3 is a longitudinal section taken on line 3-3, Fig. 1; parts being broken awayso as to better show'the construction;

Fig. 4 yis a diagram of the electric ccnnections and the manner in which the electric circuit to the heater is made and broken; and

tire retreading mould.

In Figs. 1, 2, and 3 a tube vulcanizer has been illustrated. This vulcanizer consists of a box shaped member of cast iron provided with a top 1 of considerable thickness, sides 2, 3 and ends 4 and 5( The topl has flanges 6 and 7 that lextend beyond the end walls 4 and 5 in the manner shown in Fig. 3 and these flanges project over onto and rest upon the top of the end supports 8 and 9 which are secured to the ends 4 and 5 by means of bolts 10 and are spaced from the ends by means of plates 11 that extend below the lower edge' of the ends so that they may be bent in the manner indicated by numeral 12. The-end supports 8 are provided with feet 13 that rest upon a supporting surface and with upstanding ears 14 that are perforated for the reception of the pivot bar 15 to which levers 5 is a transverse section through a' A 16 are both slidably and pivotally attached.

These levers are bent in the manner indicated byv numeral 17 and have a portion 18 that extends downwardly terminatingin a perforated hub 19 through which the pivot bar 15 extends. Below the hubs 19 are projections20 whose inclined-ends 21 are adapted to engage the side 3 and act as stops when.

the levers are moved to the dotted line position shown in Fig. 2. The levers 16 are each provided with a longitudinal slot 22 through which the bolt 23 extends. These bolts have enlarged square heads 24 that are adapted to engage with the upper surface of the blocks 25. Helical compression springs 26 surround the bolts 23 and have one end in contact with the heads 24 and the other with the washers 27 and produce a force tending y to move the bolt 23 downwardly (Fig. 2). ts 23 A nut 28 secured to the ends of the bo acts as a stop for limiting the movement of the bolt in one direction. Pawls 29 are pivoted at 30 to the levers 16 and are provided with teeth 31 that are adapted to .engage the sharp edge 32 of the top 1 for they purpose vof holding the levers against l movement against the force exerted by the spring 26. Each pawl has a handle 33 by means of whi'ch'it can be manipulated. The material i to be vulcanized is placed between the upper surface of the top 1 andthe lower surface of the block 25 but has not been shown. The y electric heater element consists of a plate of insulating material such as mica and which has been designated by numeral34. Resistance wire35 is coiled about this plateso as `tos 40 that serves as a heat insulator that prevents the escape of heat downwardly and this material is held in place by means of a sheet metal bottom 41 that in turn is held in place by the flanges 12.

The temperature is determined by means of a pressure gage 42 which employs a Bourdon tube 43 whose interior is in `communication with the pipe 44 that extends substan-A tially the entire length of'the top 1 in the lower surface of which it is embedded in the manner shown in Figs. 2 and 3. The end of the pipe 44 is closed by means of a plug 45. The ipe 44 is filled with water or some other suita le liquid which is vaporized by theK heat. Since the temperature of saturated steam or vapor varies directly with the pressure, the scale of the gage 42 can be calibrated in degrees of temperature or of pounds of pressure as may be desired.

From Fig. 4 it will be seen that the re,y

sistance coils R and R1 are connected to one pole of the source of electric supply, which has been indicated as a battery 46, by means of a conductor 47.- A conductor 48 extends from the other p'ole of the battery to the spring conductors 49 and 5() which are normally in electrical contactwith the terminals 51v and 52, respectively. From the terminals 51 and 52 conductors 53 and 54 eX- tend to the ends of the .resistance coils R and R1. When the parts are in the position shown in Fig. 4 currentwill low through both of the resistance coils. A switch 55 serves to open and close the circuit. When the pipe 44 becomeshot the liquid will be vaporized and placed under pressure and this pressure will cause the Bourdon tube 43 .to straighten, as the pressure increases the lug 56 will move towards the screw .57 and will engage this screw when the temperature reaches the maximum value; after the lug 56 engages the screw 57 any increase in pressure will move the spring 49 upwardly and away from the terminal 5l thereby breaking the circuit to the coil R. The heat generated l by the coil R1 should be just about suiicient to make up for the heat losses so that the parts will retain their temperature. Should the temperature continue to increase'after the coil R has been disconnected, the point of the screw 58 will engage the spring 50 and move it away from the termina thereby disconnecting the coil R1. Should the temperature still rise, the contact 59 will soon reach the terminal 60 thereby short circuiting the battery through wires 48 and The 61 and blowing the fuse 62. This short circuit-ing and blowing of the fuse is resorted to as a safety device because the fact that the temperature increases when both of coils R and R1 are disconnected shows that there is something radically wrong.

In Fig. 5 I have shown a cross section of a tire vulcanizing mould which isbuilt on the same principle but merely made in a different shape. The body 63 is preferably of cast metal and has electric heaters 64 embedded in the sides. A pipe 44A that corresponds in function with pipe 44 connects with the pressure gage 42 and the o eration is exactly the same as the one descri ed.

I want to call particular attention to the automatic heat control mechanism which functions to disconnect the several heater coilsione after the other so as to reduce the amountof current at each break and to gradually reduce the heat. The means for clamping the work which comprises the levers 16, pawl 29, bolt 23,v etc., are also be' lieved to be novel in this combination.

Having now described the invention what I claim as new is:

1. In a thermoresponsive device adapted to control an electric heater, a closed chamber containing a liquid, a Bourdon tube pressure indicatorY operatively connected with said chamber so as to measure the pressure therein, an electric heater comprising two Separate heatingelements connected in series, and a source of electric current having one terminal connected to the common connection of said heater element, two resilient springs, each havin yone end stationary and the other end mova le, the stationar ends being connected with the other terminal of the battery, -a stationary contact for the. free end of each of said springs and on which the free ends of the springs normallyl rest', the free ends of said heaters being each normally connected with one of said contacts, means on said Bourdon tube for engaging one of said springs and for moving it away from its contact when the pressure exceeds a predetermined amount and means carried by the last named spring for engaging the other spring and for moving it out of contact with its stationary contact when the pressure exceeds another predetermined amount.

2. 'In a thermoresponsive device adapted to control an electric heater, va closed chamber containing a liquid, a Bourdon tube pressure indicator operatively connected wlth said chamber so as to measure the pressure therein, an electric heater comprising two separate heating elements connected 1n series, and a source of electric current having one terminal connected to the `common connection of said heater element, two resilient springs, each having` one end stationary and the other end movable, the -sta^` tionary ends being connected with thelother terminal of the battery, a stationary conengaging the other spring for moving it out tact for the free end of each of said springs of Contact with its stationary Contact when and on which the free ends of the springs the pressure exceeds another predetermined normally rest, the free ends of said heaters amount, a fuse in the lead from the battery o being each normally connected with one of to the springs and means for short circuting Ysaid contacts, means on said Bourdon tube the battery through the fuse if the pressure for engaging one of said springs and for continu-es to increase after both springs have moving it away from its Contact when the been moved to circuit opening position. pressure exceeds a predetermined amount and i In testimony whereof I aix my signature. 1U means carried by the last named spring for JAMES A. CROSS. 

